The efficacy of chemotherapy for colorectal cancer with early recurrence after adjuvant chemotherapy.

Abstract

43 Background: Adjuvant chemotherapy is the standard treatment for patients with stage III colorectal cancer (CRC) underwent surgery.However, the efficacy of chemotherapy for early recurrence after adjuvant chemotherapy remains unclear. This study aimed to assess the efficacy of chemotherapy for CRC with early recurrence during or after adjuvant chemotherapy. Methods: We retrospectively reviewed CRC patients who underwent surgery at 3 institutions between 2016 and 2021. The inclusion criteria were as follows: ECOG performance status was 0 or 1, histology was adenocarcinoma, patients who received adjuvant chemotherapy following surgical resection, early recurrence during or within 12 months after adjuvant chemotherapy and no prior treatment for CRC after early recurrence. The interval from the last administration of adjuvant chemotherapy to recurrence was defined as the recurrence-free interval (RFI). Overall survival (OS), progression-free survival (PFS), objective response rates (ORR), and disease control rate (DCR) were assessed according to the RFI. Results: Of 448 patients, 32 patients were eligible. Median age was 57 years (range 26–79), 14 patients (44%) were male and ECOG performance status 0 / 1 was 29 (91%) / 3 (9%). RAS wild-type / mutant was 12 (38%) / 20 (62%) and right / left as sidedness was 21 (66%) / 11 (34%). Regarding adjuvant chemotherapy, 4 patients (12%) received single-agent therapy, while 28 patients (88%) received combination therapy with two agents. Palliative chemotherapy after early recurrence included Oxaliplatin-based regimens in 13 patients (41%), irinotecan-based regimens in another 13 patients (41%), and other regimens in 6 patients (18%). For all patients, the median PFS and OS were 10.4 months and 43.0 months, respectively. The ORR and DCR were 34.4% and 75.0%, respectively. When patients were divided into RFI < 6 months and RFI ≥ 6 months, the ORR was superior in the RFI ≥ 6 months group to RFI < 6 months group (56 % vs. 26%). The PFS (median 10.4 months vs. 17.8 months, HR 0.92; 95% Cl 0.36-2.38, p = 0.87) and OS (median 31.3 months vs. 43.0 months, HR 0.97; 95% Cl 0.31-3.08, p = 0.97) did not differ between the RFI < 6 months group and the RFI ≥ 6 months group. Multivariate analysis for OS indicated a trend toward a poor prognosis in the RFI < 6 months group compared to the RFI ≥ 6 months group (HR 1.78; 95% CI 0.35-8.98, p = 0.48). Conclusions: In patients with CRC experienced early recurrence, the RFI < 6 months group had a trend of poor efficacy compared to the RFI of ≥ 6 months group.